This invention relates to an ultrasound system and method for obtaining ultrasound data using transducer element switching. In particular, switching is used to space apart or short elements together for at least one transmission or reception of acoustic energy, and the resulting reflected echo signals are processed to obtain ultrasound data.
Ultrasound systems generally include transmitters (transmit channels), receivers, processors to control image formation and display monitors. Power supplies drive the transmitters, and control circuitry controls the ultrasound system. The transmitter provides electrical excitation waveforms to a transducer. The electric excitation waveforms are converted to acoustic energy by the transducer for imaging a target. The transducer generally includes a plurality of transducer elements which may be individually excited by respective plurality of transmitters, so each transmitter is connected to one element at any given time.
In a system providing a variable aperture, each one of a plurality of transmit channels may be connected to any one of several transducer elements using a multiplexer. One example of such a variable aperture multiplexer structure is disclosed by Cole et al. in U.S. Pat. No. 5,617,862.
The variable aperture multiplexer structure may be modified to allow a transmit channel to connect to more than one element at a time. As disclosed by Cole et al., switching means and programmability to support adjacent element shorting is provided. In order to connect one transmitter to two or more transducer elements, a multiplexer module in addition to a standard configuration is provided. In one example, the adjacent element shorting structure is used for a transducer with xcex/4-spacing of transducer elements. Cole et al. further describes connecting inner and outer elements for simultaneous transmit and receive (a type of multiplexer shorting). With reference to inner and outer active elements, filters for use in second harmonic imaging are disclosed at column 14, lines 5 through 25.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiments described below include a method and system for obtaining ultrasound data. Different aperture techniques are used for transmit than on receive. The various techniques include synthetic aperture, shorting elements, skipping elements, sliding apertures and combinations thereof.
The techniques used may also or independently vary as a function of the position of the transmit focus. Any desired aperture is used for a first focal position. One or more of shorting elements, skipping elements, synthetic aperture and combinations thereof techniques are used for a second focal position deeper than the first focal position.
Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.